Co-evolution of cosmic ray energy spectra, composition, and anisotropies

Fuente: arXiv
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Autori principali: Qiao, Bing-Qiang, Yuan, Qiang, Guo, Yi-Qing
Natura: Preprint
Pubblicazione: 2025
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author Qiao, Bing-Qiang
Yuan, Qiang
Guo, Yi-Qing
author_facet Qiao, Bing-Qiang
Yuan, Qiang
Guo, Yi-Qing
contents The origin of cosmic rays remains an unresolved fundamental problem in astrophysics. The synergy of multiple observational probes, including the energy spectra, the mass composition, and anisotropy is a viable way to jointly uncover this mystery. In this work, we propose that the energy-dependent of those observables in a wide energy range, from $O(10)$ GeV to ultrahigh energies of $10^{11}$ GeV, share quite a few correlated features, indicating a strong co-evolution which could be a consequence of the underlying origin of different source populations. We decipher these structures with a four-component model, i.e., the ensemble of Galactic sources, a local source close to the solar system, and the ensemble of two extra-galactic source populations. In this scenario, the $O(10^2)$ GV hardening and $O(10)$ TV bump is due to the contribution of the local source, the knee is due to the maximum acceleration energy of protons by the Galactic source population, the second knee is due to the maximum acceleration energy of iron nuclei by Galactic sources, the dip feature between the two knees is due to the appearance of the extra-galactic component, the ankle comes from the transition from one extra-galactic component to the other, and the spectral suppression at the highest energies arises from the acceleration limit of the second extra-galactic component. The transition from Galactic to extra-galactic origin of cosmic rays occurs around $O(10^8)$ GeV, which is smaller than the ankle energy.
format Preprint
id arxiv_https___arxiv_org_abs_2506_18118
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Co-evolution of cosmic ray energy spectra, composition, and anisotropies
Qiao, Bing-Qiang
Yuan, Qiang
Guo, Yi-Qing
High Energy Astrophysical Phenomena
The origin of cosmic rays remains an unresolved fundamental problem in astrophysics. The synergy of multiple observational probes, including the energy spectra, the mass composition, and anisotropy is a viable way to jointly uncover this mystery. In this work, we propose that the energy-dependent of those observables in a wide energy range, from $O(10)$ GeV to ultrahigh energies of $10^{11}$ GeV, share quite a few correlated features, indicating a strong co-evolution which could be a consequence of the underlying origin of different source populations. We decipher these structures with a four-component model, i.e., the ensemble of Galactic sources, a local source close to the solar system, and the ensemble of two extra-galactic source populations. In this scenario, the $O(10^2)$ GV hardening and $O(10)$ TV bump is due to the contribution of the local source, the knee is due to the maximum acceleration energy of protons by the Galactic source population, the second knee is due to the maximum acceleration energy of iron nuclei by Galactic sources, the dip feature between the two knees is due to the appearance of the extra-galactic component, the ankle comes from the transition from one extra-galactic component to the other, and the spectral suppression at the highest energies arises from the acceleration limit of the second extra-galactic component. The transition from Galactic to extra-galactic origin of cosmic rays occurs around $O(10^8)$ GeV, which is smaller than the ankle energy.
title Co-evolution of cosmic ray energy spectra, composition, and anisotropies
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2506.18118